奋斗

exert oneself;work hard;fight;struggle;strive
艰苦～work hard;work arduously/为祖国统一大业～work hard for the reunification of the motherland/为实现四个现代化目标而～strive for the goal of four modernizations/～到底struggle to the very end/～目标objective of an endeavor/～终身work all one's life for sth